我做的MCI音频，在音量大小遇到难题！大哥大姐们来帮帮我（急）

它能认识你那个字符串吗？你用的是控件还是API啊？

我用的是API
我用mciSendString已经实现了播放。暂停等操作了但是一用个这个字符串，就提示“驱动程序无法识别指定的命令”

别人的代码，看看吧Option ExplicitPrivate hmem As LongConst MMSYSERR_NOERROR = 0
Const MAXPNAMELEN = 32
Const MIXER_LONG_NAME_CHARS = 64
Const MIXER_SHORT_NAME_CHARS = 16
Const MIXER_GETLINEINFOF_COMPONENTTYPE = &H3&
Const MIXER_GETCONTROLDETAILSF_VALUE = &H0&
Const MIXER_SETCONTROLDETAILSF_VALUE = &H0&
Const MIXER_GETLINECONTROLSF_ONEBYTYPE = &H2&
Const MIXERLINE_COMPONENTTYPE_DST_FIRST = &H0&
Const MIXERLINE_COMPONENTTYPE_SRC_FIRST = &H1000&
Const MIXERLINE_COMPONENTTYPE_DST_SPEAKERS = _
               (MIXERLINE_COMPONENTTYPE_DST_FIRST + 4)
Const MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE = _
               (MIXERLINE_COMPONENTTYPE_SRC_FIRST + 3)
Const MIXERLINE_COMPONENTTYPE_SRC_LINE = _
               (MIXERLINE_COMPONENTTYPE_SRC_FIRST + 2)
Const MIXERCONTROL_CT_CLASS_FADER = &H50000000
Const MIXERCONTROL_CT_UNITS_UNSIGNED = &H30000
Const MIXERCONTROL_CONTROLTYPE_FADER = _
               (MIXERCONTROL_CT_CLASS_FADER Or _
               MIXERCONTROL_CT_UNITS_UNSIGNED)
Const MIXERCONTROL_CONTROLTYPE_VOLUME = _
               (MIXERCONTROL_CONTROLTYPE_FADER + 1)Private Type MIXERCONTROLDETAILS
    cbStruct    As Long
    dwControlID As Long
    cChannels   As Long
    item        As Long
    cbDetails   As Long
    paDetails   As Long
End TypePrivate Type MIXERCONTROLDETAILS_UNSIGNED
    dwValue As Long
End Type

Private Type MIXERCONTROL
    cbStruct       As Long
    dwControlID    As Long
    dwControlType  As Long
    fdwControl     As Long
    cMultipleItems As Long
    szShortName    As String * MIXER_SHORT_NAME_CHARS
    szName         As String * MIXER_LONG_NAME_CHARS
    lMinimum       As Long
    lMaximum       As Long
    reserved(10)   As Long
End TypePrivate Type MIXERLINECONTROLS
    cbStruct  As Long
    dwLineID  As Long
    dwControl As Long
    cControls As Long
    cbmxctrl  As Long
    pamxctrl  As Long
End TypePrivate Type MIXERLINE
    cbStruct        As Long
    dwDestination   As Long
    dwSource        As Long
    dwLineID        As Long
    fdwLine         As Long
    dwUser          As Long
    dwComponentType As Long
    cChannels       As Long
    cConnections    As Long
    cControls       As Long
    szShortName     As String * MIXER_SHORT_NAME_CHARS
    szName          As String * MIXER_LONG_NAME_CHARS
    dwType          As Long
    dwDeviceID      As Long
    wMid            As Integer
    wPid            As Integer
    vDriverVersion  As Long
    szPname         As String * MAXPNAMELEN
End Type
'
'Allocates the specified number of bytes from the heap.
Private Declare Function GlobalAlloc Lib "kernel32" (ByVal wFlags As Long, _
    ByVal dwBytes As Long) As Long
'
'Locks a global memory object and returns a pointer to the
' first byte of the object's memory block.  The memory block
' associated with a locked object cannot be moved or discarded.
Private Declare Function GlobalLock Lib "kernel32" (ByVal hmem As Long) As Long
'
'Frees the specified global memory object and invalidates its handle.
Private Declare Function GlobalFree Lib "kernel32" (ByVal hmem As Long) As Long
'
Private Declare Sub CopyPtrFromStruct Lib "kernel32" Alias "RtlMoveMemory" _
    (ByVal ptr As Long, struct As Any, ByVal cb As Long)Private Declare Sub CopyStructFromPtr Lib "kernel32" Alias "RtlMoveMemory" _
    (struct As Any, ByVal ptr As Long, ByVal cb As Long)
'
'Opens a specified mixer device and ensures that the device
' will not be removed until the application closes the handle.
Private Declare Function mixerOpen Lib "winmm.dll" _
    (phmx As Long, ByVal uMxId As Long, ByVal dwCallback As Long, _
    ByVal dwInstance As Long, ByVal fdwOpen As Long) As Long
'
'Sets properties of a single control associated with an audio line.
Private Declare Function mixerSetControlDetails Lib "winmm.dll" _
    (ByVal hmxobj As Long, pmxcd As MIXERCONTROLDETAILS, _
    ByVal fdwDetails As Long) As Long
'
'Retrieves information about a specific line of a mixer device.
Private Declare Function mixerGetLineInfo Lib "winmm.dll" _
    Alias "mixerGetLineInfoA" (ByVal hmxobj As Long, _
    pmxl As MIXERLINE, ByVal fdwInfo As Long) As Long
'
'Retrieves one or more controls associated with an audio line.
Private Declare Function mixerGetLineControls Lib "winmm.dll" _
    Alias "mixerGetLineControlsA" (ByVal hmxobj As Long, _
    pmxlc As MIXERLINECONTROLS, ByVal fdwControls As Long) As LongPrivate hmixer  As Long
Private volCtrl As MIXERCONTROL ' Waveout volume control.
Private micCtrl As MIXERCONTROL ' Microphone volume control.
'
'Local variable to save properties
Private mvarprMicVolume As Long 'Local copy
Private mvarprMicMaxVolume As Long 'Local copy
Private mvarprMicMinVolume As Long 'Local copy
Private mvarprSpeakerVolume As Long 'Local copy
Private mvarprSpeakerMaxVolume As Long 'Local copy
Private mvarprSpeakerMinVolume As Long 'Local copy
Private mvarprMixerErr As Long 'Local copyPrivate Function fGetVolumeControl(ByVal hmixer As Long, _
        ByVal componentType As Long, ByVal ctrlType As Long, _
        ByRef mxc As MIXERCONTROL) As Boolean
'
' This function attempts to obtain a mixer control.
'
Dim mxlc As MIXERLINECONTROLS
Dim mxl  As MIXERLINE
Dim hmem As Long
Dim rc   As Longmxl.cbStruct = Len(mxl)
mxl.dwComponentType = componentType
'
' Get a line corresponding to the component type.
'
rc = mixerGetLineInfo(hmixer, mxl, MIXER_GETLINEINFOF_COMPONENTTYPE)
If MMSYSERR_NOERROR = rc Then
    With mxlc
        .cbStruct = Len(mxlc)
        .dwLineID = mxl.dwLineID
        .dwControl = ctrlType
        .cControls = 1
        .cbmxctrl = Len(mxc)
    End With
    '
    ' Allocate a buffer for the control.
    '
    hmem = GlobalAlloc(&H40, Len(mxc))
    mxlc.pamxctrl = GlobalLock(hmem)
    mxc.cbStruct = Len(mxc)
    '
    ' Get the control.
    '
    rc = mixerGetLineControls(hmixer, mxlc, MIXER_GETLINECONTROLSF_ONEBYTYPE)
    If MMSYSERR_NOERROR = rc Then
        fGetVolumeControl = True
        '
        ' Copy the control into the destination structure.
        '
        Call CopyStructFromPtr(mxc, mxlc.pamxctrl, Len(mxc))
    Else
        fGetVolumeControl = False
    End If
    Call GlobalFree(hmem)
    Exit Function
End If
fGetVolumeControl = False
End Function

Private Function fSetVolumeControl(ByVal hmixer As Long, _
    mxc As MIXERCONTROL, ByVal volume As Long) As Boolean
'
' This function sets the value for a volume control.
'
Dim rc   As Long
Dim mxcd As MIXERCONTROLDETAILS
Dim vol  As MIXERCONTROLDETAILS_UNSIGNEDWith mxcd
    .item = 0
    .dwControlID = mxc.dwControlID
    .cbStruct = Len(mxcd)
    .cbDetails = Len(vol)
End With
'
' Allocate a buffer for the control value buffer.
'
hmem = GlobalAlloc(&H40, Len(vol))
mxcd.paDetails = GlobalLock(hmem)
mxcd.cChannels = 1
vol.dwValue = volume
'
' Copy the data into the control value buffer.
'
Call CopyPtrFromStruct(mxcd.paDetails, vol, Len(vol))
'
' Set the control value.
'
rc = mixerSetControlDetails(hmixer, mxcd, MIXER_SETCONTROLDETAILSF_VALUE)
Call GlobalFree(hmem)If MMSYSERR_NOERROR = rc Then
    fSetVolumeControl = True
Else
    fSetVolumeControl = False
End If
End FunctionPublic Function meOpenMixer() As Long
Dim rc  As Long
Dim bOK As Boolean
'
' Open the mixer with deviceID 0.
'
rc = mixerOpen(hmixer, 0, 0, 0, 0)
mvarprMixerErr = rc
If MMSYSERR_NOERROR <> rc Then
    MsgBox "Could not open the mixer.", vbCritical, "Volume Control"
    Exit Function
End If
'
' Get the waveout volume control.
'
bOK = fGetVolumeControl(hmixer, _
        MIXERLINE_COMPONENTTYPE_DST_SPEAKERS, _
        MIXERCONTROL_CONTROLTYPE_VOLUME, volCtrl)
'
' If the function successfully gets the volume control,
' the maximum and minimum values are specified by
' lMaximum and lMinimum.
'
If bOK Then
        mvarprSpeakerMaxVolume = volCtrl.lMaximum
        mvarprSpeakerMinVolume = volCtrl.lMinimum
End If
'
' Get the microphone volume control.
'
bOK = fGetVolumeControl(hmixer, _
        MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE, _
        MIXERCONTROL_CONTROLTYPE_VOLUME, micCtrl)If bOK Then
        mvarprMicMaxVolume = micCtrl.lMaximum
        mvarprMicMinVolume = micCtrl.lMinimum
End If
End FunctionPublic Property Get prMixerErr() As Long
    prMixerErr = mvarprMixerErr
End PropertyPublic Property Get prSpeakerMinVolume() As Long
    prSpeakerMinVolume = mvarprSpeakerMinVolume
End PropertyPublic Property Get prSpeakerMaxVolume() As Long
    prSpeakerMaxVolume = mvarprSpeakerMaxVolume
End PropertyPublic Property Let prSpeakerVolume(ByVal vData As Long)
    mvarprSpeakerVolume = vData
    Call fSetVolumeControl(hmixer, volCtrl, vData)
End PropertyPublic Property Get prSpeakerVolume() As Long
    prSpeakerVolume = mvarprSpeakerVolume
End PropertyPublic Property Get prMicMinVolume() As Long
    prMicMinVolume = mvarprMicMinVolume
End PropertyPublic Property Get prMicMaxVolume() As Long
    prMicMaxVolume = mvarprMicMaxVolume
End PropertyPublic Property Let prMicVolume(ByVal vData As Long)
    mvarprMicVolume = vData
    Call fSetVolumeControl(hmixer, micCtrl, vData)
End PropertyPublic Property Get prMicVolume() As Long
    prMicVolume = mvarprMicVolume
End Property<到这里完>

呵呵你这个好象是用mixer实现的音频。有些不相符
不过还是谢谢了
今天晚上再等等看有没有好些的答案。下班了，明天来结贴！THANKS

setaudio命令不是所有设备都会支持的，要看你播放的是什么内容，典型例子：它对Midi音乐就是无效的，但可用midiOutSetVolume调节

来了！
我播放的是.WAV文件是不是设备对.wav的文件setaudio命令也不支持呢！

应该不能用在WAV文件上吧，我印象中setaudio只可用于Digital-video and VCR devices，它只是修改解码播放设备的音量，如Mp3、Wma等，不会改变系统音量，这些文件解码后基本都是WAV输出，所以它们还可能通过系统音量做二次调节，WAV文件是直接输出的，没有解码过程，只能通过改变系统音量来调节。

哦！这样我就清楚多了
但是.wav文件如何控制音量大小呢？只能控制系统的音量？我用waveoutsetvolume倒是可以弄音量大小。这个只是修改系统的波形，如果象mediaplayer那样的音量大小调节是怎么实现的呢？
马上就结贴，大哥们再帮帮小弟我。

我的理解：利用MCI-API播放的软件只是一个功能外壳而已，根本称不上为播放器。能叫做的媒体播放器的软件，都是自己解码自已控制音频流输出最后才交给系统进行混音，而且很多一般都是支持或仅采用DirectSound方式输出音频，音量控制是独立于系统的也就很正常，前面说的setaudio命令，本质上也是调用相关设备的这种功能而已。

调试易

我做的MCI音频，在音量大小遇到难题！大哥大姐们来帮帮我（急）

解决方案 »